"As you drink more tea and coffee in your favourite mug, you may start to notice that over time the inside becomes discoloured and stained," said cleaning professional Matthew Harrison. Speaking on behalf of PriceYourJob.co.uk, Matthew revealed that tannins are the root cause of the discolouration.

He explained: "When tea [or coffee] is brewed, the calcium carbonate that is found in tap water binds with the tannins to form an insoluble substance that settles on the bottom of mugs." Yet there is one cleaning solution you might not have thought of – especially when simple soap and water don't do the job. "This one seems a little more outside of the box," admitted Mr Harrison when he mentioned the use of denture tablets.

"But tannins can stain your teeth in the same way they stain mugs, and these tablets work wonders."

He instructed: "Add the denture tablet to a mug filled with enough water to cover the stain and leave it to work before rinsing and washing the mug well with dish soap."

Sometimes, if the tannin stain is severe enough, more cleaning methods might be appropriate.

There's soaking the mug in dish soap and scrubbing the stains with a sponge, then there's denture tablets, and even baking soda.

Mr Harrison elaborated: "Sprinkle around one teaspoon of baking soda onto the stain and add some water to mix it up into a paste.

"Scrub the stain with a damp, soft sponge before thoroughly rinsing the mug."

If that still doesn't work, the other option is to "fill your mug halfway with distilled white vinegar, then up to the top with hot water".

Mr Harrison added: "Allow the mixture to sit for at least 10 minutes to give it time to work before scrubbing away the stains with a sponge and rinsing the mug."

To remove the coffee or tea stains from any mug, any one of these cleaning methods might be enough to lift the stain completely.

In some cases, a mixture of some cleaning methods might be best, but for the most severe staining, all four methods could be required.

Once the stains have been removed, it's best to wash up the mugs as soon as they've been used to help prevent further staining.